Meet E4, the self-propelled, dust-busting solar panel robot

Deserts are great places for solar farms – they get plenty of sunshine, and land is relatively inexpensive – but the hot, dry environment also produces a lot of dust. A dirty solar panel is an inefficient solar panel; depending on location and weather conditions, dust-covered panels can reduce energy production by
up to 40 percent.

Traditionally,
solar panels have been cleaned by workers using three- to four-meter poles with a squeegee attached to the end. It takes a lot of time and water – a valuable commodity in a desert – to clean an entire solar farm. And it's also risky: One wrong swing of the squeegee could crack and damage a panel.

Ecoppia, a startup based in Israel, has a different solution. The company's E4 cleaning system is a self-guided, battery-powered robot that uses microfiber cloths and controlled air flow to clean solar panels, completely water-free.

It was previously thought that photovoltaic panels should not be cleaned while dry. However, testing by the Berlin Photovoltaic Institute determined the E4's soft cloth could gently brush away the dirt without damaging the panel.

The E4 uses a regenerative braking system to capture additional energy. (Photo: Ecoppia)

At the Ketura Sun solar field in Israel's Negev desert, each row of panels has an E4 robot attached to it. Each unit has five motors: two for horizontal movement, two for vertical movement (to pull the robot up; gravity allows it to descend) and one to spin the microfiber cloth.

Other solar panel cleaning robots in development, like the
Miraikikai Wall Walker and Sinfonia's Resola, use little or no water. What makes the E4 unique is that it's completely self-contained and centrally controlled.

"You can be in San Francisco and you can easily control your solar parks in Ghana, Namibia, India and Saudi Arabia," Ecoppia CEO Eran Meller told the
Washington Post.

It takes less than 60 minutes for an E4 robot to make a complete pass over each row every night, and its battery is recharged by its own solar panel during the day. In case of cloudy weather, the E4 battery stores enough energy to power the unit for up to three days. The E4 uses Ecoppia's
proprietary regenerative braking system called Eco-Hybrid, which allows the unit to capture energy with every downward trip it makes. The microfiber cloth is also self-cleaning.

The company has already cleaned more than a million solar panels and says it has big plans for expansion. "We are on track to meet and exceed our expansion plans, such that Ecoppia robots will be cleaning 5 million panels a month by the end of the year, while adhering to the highest standards of operational excellence and customer satisfaction,"
Meller said.

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Jenn Virskus
is most often found at her computer writing (anything) or on a sailboat holding onto the end of a spinnaker sheet.